In commonly-owned U.S. Pat. No. 5,630,796 to Bellhouse et al., a non-invasive delivery system is described that entails the use of a needleless syringe. The syringe is used for transdermal delivery of powdered therapeutic compounds and compositions to skin, muscle, blood or lymph. The syringe can also be used in conjunction with surgery to deliver therapeutics to organ surfaces, solid tumors and/or to surgical cavities (e.g., tumor beds or cavities after tumor resection).
The needleless syringe is constructed as an elongate tubular nozzle, typically having a rupturable membrane initially closing the passage through the nozzle adjacent to the upstream end of the nozzle. Particles of a powdered therapeutic agent are located adjacent to the membrane. The therapeutic agent is delivered using an energizing means which applies a gaseous pressure to the upstream side of the membrane that is sufficient to burst the membrane, thereby producing a supersonic gas flow through the nozzle. The supersonic gas flow produced in the nozzle entrains the particles and accelerates them to suitable velocities for transdermal delivery into tissue such as skin or muscle.